tty: n_gsm: add missing description to structs in gsmmux.h

Currently, all available structure fields in gsmmux.h except those
for gsm_config are commented. Furthermore, no kernel doc comments are used.

Fix this by adding appropriate comments to the not commented fields of
gsm_config. Convert the comments of the other structs to kernel doc format.

Note that 'mru' and 'mtu' refer to the size without basic/advanced option
mode header and byte stuffing as defined in the standard in chapter 5.7.2.

Link: https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20230817093231.2317-2-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/uapi/linux/gsmmux.h b/include/uapi/linux/gsmmux.h
index e56e2d7..3bd6f03 100644 (file)
--- a/include/uapi/linux/gsmmux.h
+++ b/include/uapi/linux/gsmmux.h
@@ -18,6 +18,28 @@
  */
 #define GSM_FL_RESTART _BITUL(0)
 
+/**
+ * struct gsm_config - n_gsm basic configuration parameters
+ *
+ * This structure is used in combination with GSMIOC_GETCONF and GSMIOC_SETCONF
+ * to retrieve and set the basic parameters of an n_gsm ldisc.
+ * struct gsm_config_ext can be used to configure extended ldisc parameters.
+ *
+ * All timers are in units of 1/100th of a second.
+ *
+ * @adaption:      Convergence layer type
+ * @encapsulation: Framing (0 = basic option, 1 = advanced option)
+ * @initiator:     Initiator or responder
+ * @t1:            Acknowledgment timer
+ * @t2:            Response timer for multiplexer control channel
+ * @t3:            Response timer for wake-up procedure
+ * @n2:            Maximum number of retransmissions
+ * @mru:           Maximum incoming frame payload size
+ * @mtu:           Maximum outgoing frame payload size
+ * @k:             Window size
+ * @i:             Frame type (1 = UIH, 2 = UI)
+ * @unused:        Can not be used
+ */
 struct gsm_config
 {
        unsigned int adaption;
@@ -31,18 +53,32 @@ struct gsm_config
        unsigned int mtu;
        unsigned int k;
        unsigned int i;
-       unsigned int unused[8]; /* Can not be used */
+       unsigned int unused[8];
 };
 
 #define GSMIOC_GETCONF         _IOR('G', 0, struct gsm_config)
 #define GSMIOC_SETCONF         _IOW('G', 1, struct gsm_config)
 
+/**
+ * struct gsm_netconfig - n_gsm network configuration parameters
+ *
+ * This structure is used in combination with GSMIOC_ENABLE_NET and
+ * GSMIOC_DISABLE_NET to enable or disable a network data connection
+ * over a mux virtual tty channel. This is for modems that support
+ * data connections with raw IP frames instead of PPP.
+ *
+ * @adaption: Adaption to use in network mode.
+ * @protocol: Protocol to use - only ETH_P_IP supported.
+ * @unused2:  Can not be used.
+ * @if_name:  Interface name format string.
+ * @unused:   Can not be used.
+ */
 struct gsm_netconfig {
-       unsigned int adaption;  /* Adaption to use in network mode */
-       unsigned short protocol;/* Protocol to use - only ETH_P_IP supported */
-       unsigned short unused2; /* Can not be used */
-       char if_name[IFNAMSIZ]; /* interface name format string */
-       __u8 unused[28];        /* Can not be used */
+       unsigned int adaption;
+       unsigned short protocol;
+       unsigned short unused2;
+       char if_name[IFNAMSIZ];
+       __u8 unused[28];
 };
 
 #define GSMIOC_ENABLE_NET      _IOW('G', 2, struct gsm_netconfig)
@@ -51,27 +87,55 @@ struct gsm_netconfig {
 /* get the base tty number for a configured gsmmux tty */
 #define GSMIOC_GETFIRST                _IOR('G', 4, __u32)
 
+/**
+ * struct gsm_config_ext - n_gsm extended configuration parameters
+ *
+ * This structure is used in combination with GSMIOC_GETCONF_EXT and
+ * GSMIOC_SETCONF_EXT to retrieve and set the extended parameters of an
+ * n_gsm ldisc.
+ *
+ * All timers are in units of 1/100th of a second.
+ *
+ * @keep_alive:  Control channel keep-alive in 1/100th of a second (0 to disable).
+ * @wait_config: Wait for DLCI config before opening virtual link?
+ * @reserved:    For future use, must be initialized to zero.
+ */
 struct gsm_config_ext {
-       __u32 keep_alive;       /* Control channel keep-alive in 1/100th of a
-                                * second (0 to disable)
-                                */
-       __u32 wait_config;      /* Wait for DLCI config before opening virtual link? */
-       __u32 reserved[6];      /* For future use, must be initialized to zero */
+       __u32 keep_alive;
+       __u32 wait_config;
+       __u32 reserved[6];
 };
 
 #define GSMIOC_GETCONF_EXT     _IOR('G', 5, struct gsm_config_ext)
 #define GSMIOC_SETCONF_EXT     _IOW('G', 6, struct gsm_config_ext)
 
-/* Set channel accordingly before calling GSMIOC_GETCONF_DLCI. */
+/**
+ * struct gsm_dlci_config - n_gsm channel configuration parameters
+ *
+ * This structure is used in combination with GSMIOC_GETCONF_DLCI and
+ * GSMIOC_SETCONF_DLCI to retrieve and set the channel specific parameters
+ * of an n_gsm ldisc.
+ *
+ * Set the channel accordingly before calling GSMIOC_GETCONF_DLCI.
+ *
+ * @channel:  DLCI (0 for the associated DLCI).
+ * @adaption: Convergence layer type.
+ * @mtu:      Maximum transfer unit.
+ * @priority: Priority (0 for default value).
+ * @i:        Frame type (1 = UIH, 2 = UI).
+ * @k:        Window size (0 for default value).
+ * @flags:    DLCI specific flags.
+ * @reserved: For future use, must be initialized to zero.
+ */
 struct gsm_dlci_config {
-       __u32 channel;          /* DLCI (0 for the associated DLCI) */
-       __u32 adaption;         /* Convergence layer type */
-       __u32 mtu;              /* Maximum transfer unit */
-       __u32 priority;         /* Priority (0 for default value) */
-       __u32 i;                /* Frame type (1 = UIH, 2 = UI) */
-       __u32 k;                /* Window size (0 for default value) */
-       __u32 flags;            /* DLCI specific flags. */
-       __u32 reserved[7];      /* For future use, must be initialized to zero */
+       __u32 channel;
+       __u32 adaption;
+       __u32 mtu;
+       __u32 priority;
+       __u32 i;
+       __u32 k;
+       __u32 flags;
+       __u32 reserved[7];
 };
 
 #define GSMIOC_GETCONF_DLCI    _IOWR('G', 7, struct gsm_dlci_config)